Table of Contents

Overview

Oregon’s Sea Level is Rising

Because the land beneath Oregon has been rising faster than the ocean, there hasn’t been any major sea level rise off the state’s coast in recent history.1 However, sea levels are projected to rise 6 inches in the next 16 years2 due to faster rates of ice melt3 and increased thermal expansion.4 Solutions in Oregon are urgent because the state has many coastal estuaries that protect inland communities and help support the state’s economy.5 While the state is beginning to plan for sea level rise and mitigate flooding, Oregon will need solutions at the local, state, and federal levels to protect its coastal communities.

Sea level rise is speeding up

Oregon’s speed of sea level rise is expected to rise significantly in the future.1 Scientists know this because the sea level is measured every 6 minutes using equipment like satellites, floating buoys off the coast, and tidal gauges to accurately measure the local sea level as it accelerates and changes.7

Created with Highcharts 6.2.0

Sea level measurement from Astoria area tide gauge since 1950

Causes & Complications

Why Are Sea Levels Rising?

Sea level rise is slower in some regions because the Earth’s tectonic plates are shifting the land upwards.8 While this has prevented sea level rise in Oregon in the past, sea level rise is now speeding up and the ocean is starting to rise faster than the land is. Because the rate of ice melt has been increasing significantly since 1992, Oregon is particularly vulnerable to an increased rate of sea level rise in the future.2Click here to learn more about the causes of sea level rise.

How Ice Melt Increases Sea Level Rise

How Thermal Expansion Increases Sea Level Rise

El Niño can worsen West Coast flooding

In Oregon, sea level rise and flooding can be impacted by El Niño weather events, which cause warmer ocean temperatures in the Pacific Ocean off the West Coast.9 Because water expands as it warms, El Niño events can raise coastal sea levels for several months.10 Although an El Niño decreases rainfall in Oregon, it also causes bigger winter waves, which increase flooding and coastal erosion.11

Forecast

What's the Future of Sea Level Rise?

Despite being relatively stable for the last decade,1 scientists now forecast that in the next 16 years, the sea level around Oregon will rise as much as 6 inches.12

Scientists are not certain how fast the ocean will warm and ice will melt. They expect water levels to continue to rise faster, but are not sure just how fast. Therefore scientists from the National Oceanic and Atmospheric Administration (NOAA) and the US Army Corps of Engineers (USACE) have made predictions based on ranges from low to high.

Below you can see the range of the NOAA and USACE high and intermediate forecasts for various locations around Oregon.13 Currently, the USACE high forecast, seen as the darkest red line, is the most likely projection.

Port Orford

Created with Highcharts 6.2.0Port Orford Sea Level Rise Forecasts

Costs

What's at Risk in Oregon?

There’s a lot at risk from sea level rise and flooding in Oregon. Nearshore fisheries and the state’s economy rely on important coastal wetlands, which are threatened by coastal erosion and flooding caused by sea level rise. Habitats crucial for salmon and shellfish, for example, can be damaged by warmer waters associated with sea level rise.14 In addition, higher seas could leave low-lying communities that are inland from estuaries exposed and unprotected from flooding, putting homes and property at danger.14